Hepatobiliary cystoadenoma: diagnostic uncertainty

Background. Hepatobiliary cystadenoma is a rare tumour that can be clinically 'silent' and only discovered as an incidental finding on ultrasonography (US). It can also be symptomatic with abdominal pain and jaundice or develop internal bleeding and (exceptionally) malignant degeneration. Therefore the treatment of choice is liver resection. Case outline. A 77-year-old woman was admitted with mild jaundice and right hypochondrial pain. For 7 years she had been known to have a silent liver lesion, always considered to be a simple cyst on US. US and CT scan revealed a multi-septate mass involving segments IV, V and VIII of the liver, with thick walls, no calcifications and no contrast enhancement US-guided aspiration showed the presence of old blood-stained material. The patient was operated with a suspected diagnosis of bleeding into a simple cyst. A Lin fenestration was performed with wide excision of the anterior wall of the cyst. Pathological examination demonstrated a mucinous hepatobiliary cystadenoma. The postoperative course was uneventful, and follow-up at 2 years confirmed no recurrence. Discussion. Imaging will normally help to distinguish the occasional hepatobiliary cystadenoma from the common simple cyst. Otherwise, when a complication occurs, preoperative differentiation may become impossible, and requires histological examination of the cyst after surgical removal.